On Tue, Aug 26, 2025 at 02:38:16PM +0200, Pratyush Yadav wrote: > When specifying fixed sized scratch areas, the parser only parses the > three scratch sizes and ignores the rest of the argument. This means the > argument can have any bogus trailing characters. > > For example, "kho_scratch=256M,512M,512Mfoobar" results in successful > parsing: > > [ 0.000000] KHO: scratch areas: lowmem: 256MiB global: 512MiB pernode: > 512MiB > > It is generally a good idea to parse arguments as strictly as possible. > In addition, if bogus trailing characters are allowed in the kho_scratch > argument, it is possible that some people might end up using them and > later extensions to the argument format will cause unexpected breakages. > > Make sure the argument is fully consumed after all three scratch sizes > are parsed. With this change, the bogus argument > "kho_scratch=256M,512M,512Mfoobar" results in: > > [ 0.000000] Malformed early option 'kho_scratch' > > Signed-off-by: Pratyush Yadav <[email protected]>
Reviewed-by: Mike Rapoport (Microsoft) <[email protected]> > --- > kernel/kexec_handover.c | 4 ++++ > 1 file changed, 4 insertions(+) > > diff --git a/kernel/kexec_handover.c b/kernel/kexec_handover.c > index ecd1ac210dbd7..a90d55121a7a0 100644 > --- a/kernel/kexec_handover.c > +++ b/kernel/kexec_handover.c > @@ -446,6 +446,10 @@ static int __init kho_parse_scratch_size(char *p) > p = endp; > } > > + /* The string should be fully consumed by now. */ > + if (*p) > + return -EINVAL; > + > scratch_size_lowmem = sizes[0]; > scratch_size_global = sizes[1]; > scratch_size_pernode = sizes[2]; > -- > 2.47.3 > -- Sincerely yours, Mike.
